More than 30 current and former NFL players participated in a Las Vegas contest called the Pro Football Arm Wrestling Championship this weekend, which is exactly what it sounds like. But even though the tournament is relatively high-profile (a broadcast deal with CBS), has been marketing some of the league’s biggest stars as participants (Rob Gronkowski, James Harrison), and is partnered with the NFLPA’s official partner charity (the Giving Back Fund), the NFL is now saying that it did not know of the contest before this weekend and is considering fines for players who participated.

The contest took place at the MGM Hotel and Casino, and the league’s gambling policy prohibits players from appearing at promotional events at casinos.

“Had we been asked in advance if this was acceptable, we would have indicated that it was in direct violation of the gambling policy,” Joe Lockhart, the NFL’s executive vice president for communications and public affairs, told USA Today. “No one sought pre-approval.”

Event organizer Alan Brickman disputed this, telling USA Today that he first sought approval from the NFL more than two months ago. He claimed that power was turned off on all gambling machines near the contest in an attempt to comply with league gambling policy and avoid trouble for players.

Other participants in the tournament included Kenny Stills, Maurkice Pouncey, Marshawn Lynch and LaMarr Woodley. It will be broadcast on CBS over two weekends beginning in May.